Sodium and potassium are elements of the same group. Potassium is placed below sodium. When a small piece of sodium and potassium of the same size are put into different containers containing distilled water, it was found that potassium spins more vigorously. Which of the following statements shows that potassium is more reactive than sodium?

Diagram 45 shows a test tube containing glacial ethanoic acid and blue litmus paper. It was found that there was no change on the litmus paper. What should be done to cause the blue litmus paper turns red?

In an experiment, 2g of magnesium powder is added to 50 cm3 of 0.2 mol dm–3 zinc sulphate solution. The temperature of the mixture increases by 12 °C. What is the heat of displacement in the experiment?